Wooden pallets, boxes and containers are commonly used for shipping products and material. One problem with using wooden shipping containers is that the wood can contain and thereby facilitate the spread of insect pests such as wood boring beetles. This is particularly a problem for international shipping because infested wood containers can introduce invasive and destructive species to new areas. Destructive species can cause billions of dollars of damage to forests and wood products industries and create long-lasting pest control problems. There is therefore an urgent need for methods to reliably kill pests within wood materials used for shipping containers.
To prevent the spread of destructive insect pests in wood and other materials, the United States and its trading partners have adopted regulations known as the International Standard for Phytosanitary Measures (ISPM). Presently, these regulations require heat treatment of wood shipping materials at least 56 degrees Celsius for 30 minutes, or fumigation in methyl bromide. Though effective for killing pests, these methods for wood treatment are problematic. Heat treatment is energy intensive and therefore expensive. Methyl bromide is toxic, is damaging to the Earth's ozone layer and can affect the appearance and properties of the wood. Methyl bromide can also render the wood unsuitable for certain uses.
Another problem with both heat treatment and fumigation is that the wood must be “stickered” (separated with spacers to provide air gaps) before treatment so that heat and chemicals can penetrate the lumber stack. Stickering a pile of lumber is time consuming and labor intensive because the entire stack must be manipulated and interleaved with air spacers. Eliminating the stickering step would significantly reduce the time and cost of wood treatment.
Due to the importance of eliminating invasive insect pests, and the problems inherent in conventional methods for wood pest control, there is an urgent need for new methods for controlling wood pests. It would be particularly beneficial to provide a method for controlling wood insect pests that is environmentally benign, inexpensive and energy efficient. Additionally, a method that does not require stickering would provide significant cost advantages.